So, in this day and age it is not clear to me what a travel agents do and how they make their livings from our trips. We’ve not used a travel agent in 40+ years. So much can be accomplished ourselves on line. We usually travel independently though we have done a two guided tours, as well as some “self-guided” e-bike tours.
As to guided tours, they run more than travelling on our own, at least in our limited experience with guided tours: Croatia guided bike tour 2018 and RS Sicily 2024. From our 2024 TR (https://community.ricksteves.com/travel-forum/trip-reports/southern-italy-30-days-three-ways-to-travel):
LATE NOTE - Now that our credit card bills are all in
Rick Steves Tour (double occupancy), plus the two extra days in Sicily ran about $640 per day, including meals on our own plus the extra day at each end. The number of specialty guides and experiences is likely a factor.
Puglia, including the self-guided bike tour, 4 more days in Puglia on our own, and including the airfare from Catania to Bari ran about $431 per day.
The final 6 nights on our own, including the rental car from Lecce to Naples, the ferry to/from Ischia and the private tour guide in Pompeii ran about $506 per day, including a couple of hundred dollars in clothing that we acquired in the Naples area....
Compare different guided tour vendors, e.g., RS, Road Scholar, Overseas Adventure Travels (OAT) and more. See: https://community.ricksteves.com/travel-forum/general-europe/comparing-tour-companies
Given where you want to travel, perhaps independent travel may work better for you in seeing all the places you want to visit. Or, maybe you combine a short 7-day or so guided tour plus independent travel at one end to add Abruzzo or Sicily, though the practicalities of adding Sicily to your otherwise central Italy destinations may challenge your budget.
Spend time with multiple guidebooks. Not just RS. DK Eyewitness, Lonely Planet, Moon, Michelin Green Guides are ones that I like. Regional guidebooks typically go deeper than country-wide guidebooks.
If you travel independently, your biggest costs - once in Italy - will be hotels and food, assuming you don’t drop a lot of money on 1/2-day or full-day guided tours. Expedia.com or hotels.com will help you find hotels and help you get senses of pricing. 2 star, 3 star, 4 star? If you find a hotel on one of those websites, see if you can save by booking directly with the hotel, rather than through Expedia or hotels.com.
Comfort/location/amenities vs costs? We travelled 2 star hotels 25 years ago. We do mostly 3 and some 4 star hotels now. Since you have a lot you want to see, you may choose more economical lodgings to meet your budget and extend your trip.
Put together a little calendar on a piece of paper. Plot out a 12 day trip on your own, with a sensible itinerary based on your research and a map. I suggest 12 days with the thought of a $500 per day budget, or $6,000 for c. 12 days in Italy, plus one travel day (and an overnight transatlantic flight) at the front and one more travel day at the back would be 14 or 15 days total. 4 nights, 3 full days in Rome? Travel day plus 3 full days in Abruzzo? Travel to Bologna for two nights (one full day). Then travel to Florence for two nights (one one full day)? Then fly home from Florence? Maybe you can add one more day and night to Bologna or Florence?
Fly “open jaw” - in to Rome and home from Florence?
As to insurance, that is a whole different story. Our 9th international trip in the past 26 years is coming up. First time we’ve bought insurance, and we limited this to emergency evacuation coverage with a limited health insurance benefit since we are over 70 and we will be cycling 13 of our 30 days in Europe. (What if we fall?) IMHO, FWIW, trip cancellation insurance costs too much and the cost:benefit ratio just did not add up.